The MEG experiment makes use of one of the world's most intense low energy muon beams, in order to search for the lepton flavour violating process Formula omitted. We determined the residual beam ...polarization at the thin stopping target, by measuring the asymmetry of the angular distribution of Michel decay positrons as a function of energy. The initial muon beam polarization at the production is predicted to be Formula omitted by the Standard Model (SM) with massless neutrinos. We estimated our residual muon polarization to be Formula omitted at the stopping target, which is consistent with the SM predictions when the depolarizing effects occurring during the muon production, propagation and moderation in the target are taken into account. The knowledge of beam polarization is of fundamental importance in order to model the background of our Formula omitted search induced by the muon radiative decay: Formula omitted.
Nanostructured tungsten and tungsten oxide films have been synthesized by pulsed laser deposition (PLD) in different atmospheres (He, Ar, dry air). The control of the gas pressure in the deposition ...chamber allows to vary the morphology of the deposited films (studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM)) ranging from a compact ultrasmooth structure to a porous nano and mesostructure characterized by a high fraction of voids and by a large specific area. The presence, the structure and the degree of crystallinity of tungsten oxide have been investigated by Raman spectroscopy. By varying the pressure of the background inert gas (He, Ar) in the 1–1000
Pa range we obtain metallic films with different degrees of spontaneous oxidation when exposed to the atmosphere. Deposition in dry air permits to grow nanostructured tungsten oxide films characterized by different degrees of crystallinity, ranging from amorphous to nanocrystalline.
CaloCube is an R&D project borne to develop a novel calorimeter design, optimized for high-energy cosmic ray measurements in space. A small prototype made of CsI(Tl) elements has been built and ...tested on particle beams. A final version, made of 5×5×18 crystals and with dual readout (two photodiodes for each crystal), to cover the full required dynamic range, is under construction and will be tested at CERN SPS in Summer 2016. The dual readout compensation technique were developed and the feasibility to extract Čerenkov signals from CsI crystals verified.
The direct observation of high-energy cosmic rays, up to the PeV region, will increasingly rely on highly performing calorimeters, and the physics performance will be primarily determined by their ...geometrical acceptance and energy resolution. Thus, it is extremely important to optimize their geometrical design, granularity, and absorption depth, with respect to the total mass of the apparatus, which is among the most important constraints for a space mission. Calocube is a homogeneous calorimeter whose basic geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic scintillating crystals. This design forms the basis of a three-year R &D activity which has been approved and financed by INFN. A comparative study of different scintillating materials has been performed. Optimal values for the size of the crystals and spacing among them have been studied. Different geometries, besides the cubic one, and the possibility to implement dual-readout techniques have been investigated. A prototype, instrumented with CsI(Tl) cubic crystals, has been constructed and tested with particle beams. An overview of the obtained results will be presented and the perspectives for future space experiments will be discussed.
Purpose: To assess the impact on local control and survival of intraoperative radiotherapy (IORT) in resectable pancreatic adenocarcinoma.
Methods and Materials: The outcome of 127 patients ...surgically treated with curative intent combined with IORT was compared with the therapeutic results of 76 patients treated with surgery as exclusive treatment.
Results: Operative mortality and morbidity were similar in IORT and no-IORT patients. In 49 patients with locally limited disease (Stage I–II; LLD), IORT (
n = 30) reduced the local failure rate and significantly prolonged time to local failure (TTLF), time to failure (TTF), and overall survival (OS) with respect to surgery alone (
n = 19). The multivariate analyses, stratifying patients by age, tumor grade, resection margins, chemotherapy, and external-beam radiotherapy use, confirmed the independent impact of IORT on outcome.
In patients with locally advanced disease (Stage III–IVA; LAD), IORT had an impact on local failure rate and on TTLF when combined with beam energies of greater than 6 MeV, whereas no effect on TTF and OS was observed.
Conclusion: IORT did not increase operative mortality and morbidity and achieved a significant improvement in local control and outcome in patients with LLD. In patients with LAD, beam energies greater than 6 MeV prolonged TTLF.
We studied the radiative muon decay
μ
+
→
e
+
ν
ν
¯
γ
by using for the first time an almost fully polarized muon source. We identified a large sample (
∼
13,000) of these decays in a total sample of
...1.8
×
10
14
positive muon decays collected in the MEG experiment in the years 2009–2010 and measured the branching ratio
B
(
μ
→
e
ν
ν
¯
γ
)
=
(
6.03
±
0.14
(
stat
.
)
±
0.53
(
sys
.
)
)
×
10
-
8
for
E
e
>
45
MeV
and
E
γ
>
40
MeV
, consistent with the Standard Model prediction. The precise measurement of this decay mode provides a basic tool for the timing calibration, a normalization channel, and a strong quality check of the complete MEG experiment in the search for
μ
+
→
e
+
γ
process.
Purpose: To evaluate clinical and lung dose–volume histogram based factors as predictors of radiation pneumonitis (RP) in lung cancer patients (PTs) treated with thoracic irradiation.
Methods and ...materials: Records of all lung cancer PTs irradiated at our Institution between 1994 and 2000 were retrospectively reviewed. Eighty-four PTs with small or non-small-cell lung cancer, irradiated at >40 Gy, with full 3D dosimetry data and a follow-up time of >6 months from start of treatment, were analysed for RP. Pneumonitis was scored on the basis of SWOG toxicity criteria and was considered a complication when grade≥II. The following clinical parameters were considered: gender, age, surgery, chemotherapy agents, presence of chronic obstructive pulmonary disease (COPD), performance status. Dosimetric factors including prescribed dose (D
iso), presence of final conformal boost, mean lung dose (D
mean), % of lung receiving ≥20, 25, 30, 35, 40, and 45 Gy (respectively V
20→V
45), and normal tissue complication probability (NTCP) values were analysed. DVHs data and NTCP values were collected for both lungs considered as a paired organ. Median and quartile values were taken as cut-off for statistical analysis. Factors that influenced RP were assessed by univariate (log-rank) and multivariate analyses (Cox hazard model).
Results: There were 14 PTs (16.6%) who had ≥grade II pulmonary toxicity. In the entire population, the univariate analysis revealed that many dosimetric parameters (D
iso, V
20, V
30, V
40, V
45) were significantly associated with RP. No significant correlation was found between the incidence of RP and D
mean or NTCP values. Multivariate analysis revealed that the use of mitomycin (MMC) (
P=0.005) and the presence of COPD (
P=0.026) were the most important risk factor for RP. In the group without COPD (55 PTs, seven RP) a few dosimetric factors (D
mean, V
20, V
45) and NTCP values (all models) were associated with RP in the univariate analysis (
P≤0.06). According to the multivariate analysis, the use of MMC was independently associated with RP (
P=0.007), while D
mean approached statistical significance (
P=0.082).
Conclusions: In this study the use of mitomycin or the presence of COPD is associated with a higher risk of RP. In the entire population NTCP values were not significantly correlated with the incidence of RP. Mean lung dose shows a clear trend toward statistical significance in the patient group without COPD.
This text covers basic techniques from algebra and number theory which have recently proven to be extremely useful for applications to cryptography and coding theory. Public key cryptography is ...extensively discussed, and quantum cryptography is covered.
The Jacobian of the deformation field of the registration between images taken during Radiotherapy is a measure of compression/expansion of the voxels within an organ. The Jacobian mean value was ...applied to investigate possible correlations between parotid deformation and anatomical, clinical and dosimetric parameters. Data of 84 patients were analyzed. Parotid deformation was evaluated through Jacobian maps of images taken at the start and at the end of the treatment. Several clinical, geometrical and dosimetric factors were considered. Correlation between Jacobian mean value and these parameters was assessed through Spearman’s test. Univariate and multivariate logistic analyses were performed by considering as the end point the first quartile value of the Jacobian mean value. Parotid dose volume histograms were stratified according to gland deformation, assessing the most predictive dose-volume combination. At multivariate analysis, age (p = 0.02), overlap between tumor volume and parotid gland (p = 0.0006) and the parotid volume receiving more than 10 Gy (p = 0.02) were found as the best independent predictors, by considering Jacobian mean value <first quartile as the end point. By comparing the average dose volume histogram of parotids with Jacobian mean value <first quartile and >fist quartile, the parotid volume receiving more than 10 Gy and 40 Gy were found as the most predictive dosimetric parameters. Parotid glands were divided in three different sub-groups (bad-, medium- and good dose volume histogram). The risk to have Jacobian means value lower than first quartile was 39.6% versus 19.6% versus 11.3% in these three groups. By including in the multivariate analysis this “dose volume grouping” parameter, age and bad dose volume histogram were found as the most predictive parameters for large shrinkage. The pattern of parotid deformation may be well predicted by some pre-treatment variables; a bad dose volume histogram seems the most important predictor.
Future space experiments dedicated to the observation of high-energy gamma and cosmic rays will increasingly rely on a highly performing calorimetry apparatus, and their physics performance will be ...primarily determined by the geometrical dimensions and the energy resolution of the calorimeter deployed. Thus it is extremely important to optimize its geometrical acceptance, the granularity, and its absorption depth for the measurement of the particle energy with respect to the total mass of the apparatus which is the most important constraint for a space launch. The proposed design tries to satisfy these criteria while staying within a total mass budget of about 1.6 tons. Calocube is a homogeneous calorimeter instrumented with Cesium iodide (CsI) crystals, whose geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is more than adequate for optimal electromagnetic particle identification and energy measurement, whilst the interaction length is at least suficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. The design forms the basis of a three-year R&D activity which has been approved and financed by INFN. An overall description of the system, as well as results from preliminary tests on particle beams will be described.
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